Horseplayers have four days to shop the Belmont Stakes, to sort the contenders, discard the pretenders — and line up the bets.

In search of a professional evaluation, I called Jerry Brown, the speed chart connoisseur and proprietor of Thoro-graph, to get a line on the race that has thrown up one long shot surprise after another in the past 10 years.

He started with I’ll Have Another, the Kentucky Derby and Preakness winner, who will be a short-priced favorite to sew it all up in the Belmont.

“I’ll Have Another is the best and fastest horse in the race,” Brown said. “The problem is that he ran much faster in the Preakness than he had ever done before, and four [Charismatic, Funny Cide, Curlin and Shackleford] out of the last five horses who ran their lifetime best in the Preakness lost the Belmont.”

(Actually, the fifth horse, Real Quiet, ran his race but lost the Belmont in a photo finish.)

Ouch! Does this mean I’ll Have Another is in big trouble?

“Not necessarily,” Brown said. “He could run four or five lengths slower in the Belmont and still beat these horses.”

Enter the price factor. Most morning-line experts have pegged I’ll Have Another as an odds-on favorite.

“And that makes him a bad bet,” Brown said. “I’ll Have Another could win it, but other horses have an equal chance of winning at much better odds.”

The one horse catching his attention is Paynter, the lightly raced colt trained by Bob Baffert and listed at 15-1 in the Post morning line. Paynter ran fourth in the Santa Anita Derby, second in the Derby Trial at Churchill Downs, then smoked an allowance field at Pimlico by nearly six lengths to ring up a huge 106 Beyer speed figure.

Since then, he has worked a bullet five-furlong work in 59.1 seconds breezing, the fastest of 41 horses working that morning at Belmont. With this background, he looks the speed of the Belmont.

Early in the year, Baffert thought Paynter might be his star three-year-old, but then Bodemeister came along and destroyed the Arkansas Derby field and he became the hope of the side.

Paynter has a very thin foundation. He didn’t have his first race until February this year and he has had only four starts, so tackling these at a mile and a half is asking him to climb a mountain.

“But he’s fast enough, he’s good enough to win and he’s fresh, and if he had had more time I would really like him.” Brown said.

The horse Brown is really focusing on is Dullahan, the fast closing third in the Kentucky Derby after winning the Blue Grass on Keeneland’s synthetic surface with a furious closing rush.

“At this point, he’s a few lengths behind I’ll Have Another,” Brown said. “But if he’s ready to run his race, the question then becomes whether he is good enough. I think he’s 50-50 to run better than he has to date, he will certainly run as good as he ever has before, He’s fresh, he’s going the right way, I like him in this race and for the rest of the year.”

Brown is wary of Union Rags, the overwhelming winter book favorite to win the Kentucky Derby but now looms, by far, the biggest disappointment of the season. He won the Fountain of Youth at Gulfstream by four lengths, but then lost the Florida Derby as the 2-5 favorite and ran a dismal seventh in the Kentucky Derby.

“I don’t give him nearly as much excuse for his Florida failure as others do,” Brown said. “He didn’t do much running when he got in the clear. In the Kentucky Derby, he was far back early and he made up some ground only because the horses in front of him were collapsing.

“I’m not convinced this horse is moving in the right direction.”

To sum up: “I don’t think I’ll Have Another is going to run as well here as he did in the Preakness,” Brown said. “You’re going to get five or six times the price on Dullahan and Paynter as you’re going to get on I’ll Have Another with roughly the same chance of winning the race.

“Dullahan is the play and I’ll probably use him with Paynter in the exotics.”